What is the initial treatment for pneumonia?

Initial Treatment for Pneumonia

For community-acquired pneumonia (CAP), the initial empiric antibiotic therapy should be based on the patient's risk factors, severity of illness, and treatment setting, with a β-lactam plus a macrolide being the recommended regimen for hospitalized non-ICU patients. 1, 2

Outpatient Treatment

• For previously healthy outpatients with no risk factors for drug-resistant pathogens, a macrolide (e.g., azithromycin) is recommended as first-line therapy 1, 2
• For outpatients with comorbidities or recent antibiotic use, a respiratory fluoroquinolone (e.g., levofloxacin, moxifloxacin) or a β-lactam plus a macrolide is recommended 1, 2
• Amoxicillin 1 g every 8 hours is an alternative first-line therapy for outpatients without comorbidities 2
• Doxycycline 100 mg twice daily can be used as an alternative first-line option for outpatients without comorbidities 2

Hospitalized Non-ICU Patients

• Standard regimen options include β-lactam (e.g., ceftriaxone) plus a macrolide (e.g., azithromycin) 1, 2
• A respiratory fluoroquinolone alone (levofloxacin or moxifloxacin) is an acceptable alternative treatment option 1, 2
• Combined oral therapy with amoxicillin and a macrolide (erythromycin or clarithromycin) is preferred for patients who require hospital admission for clinical reasons 3

Severe CAP/ICU Treatment

• For patients without risk factors for Pseudomonas, a β-lactam plus either a macrolide or a respiratory fluoroquinolone is recommended 1, 2
• For patients with risk factors for Pseudomonas, an antipseudomonal β-lactam plus either ciprofloxacin or levofloxacin, an aminoglycoside plus azithromycin, or an aminoglycoside plus an antipneumococcal fluoroquinolone is recommended 1, 2
• Intravenous combination of a broad-spectrum β-lactamase stable antibiotic such as co-amoxiclav or a second/third generation cephalosporin together with a macrolide is preferred for severe pneumonia 3

Timing and Duration of Therapy

• Antibiotic treatment should be initiated immediately after diagnosis of CAP 1, 2
• For patients admitted through the emergency department, the first antibiotic dose should be administered while still in the ED 3
• The minimum duration of therapy is 5 days, with the patient required to be afebrile for 48-72 hours and have no more than one sign of clinical instability before discontinuing therapy 3, 1
• Treatment should generally not exceed 8 days in a responding patient 2
• Patients should be switched from intravenous to oral therapy when they are hemodynamically stable and improving clinically, are able to ingest medications, and have a normally functioning gastrointestinal tract 3

Special Considerations

• Once the etiology of CAP has been identified, antimicrobial therapy should be directed at that specific pathogen 3, 1
• For Legionella spp., levofloxacin, moxifloxacin, or macrolide (azithromycin preferred) with or without rifampicin is recommended 1
• For atypical pathogens (Mycoplasma, Chlamydophila), macrolides, doxycycline, or respiratory fluoroquinolones are recommended 1
• Adding vancomycin or linezolid should be considered when community-acquired MRSA is suspected, with risk factors including prior MRSA infection, recent hospitalization, or recent antibiotic use 2

Common Pitfalls and Caveats

• Overreliance on fluoroquinolones can lead to resistance; they should be reserved for patients with β-lactam allergies or when specifically indicated 2
• Inadequate coverage for atypical pathogens should be avoided 2
• Azithromycin should not be used in patients with known prolongation of the QT interval, a history of torsades de pointes, congenital long QT syndrome, bradyarrhythmias or uncompensated heart failure 4
• Penicillin by the intramuscular route is the usual drug of choice in the treatment of Streptococcus pyogenes infection and the prophylaxis of rheumatic fever 4
• Failure to adjust therapy based on culture results can lead to unnecessary prolonged therapy 2

Recent evidence suggests that initial adequate antibiotic therapy markedly decreases 60-day mortality in CAP patients. While dual therapy improves the likelihood of initial adequate therapy, it has not been shown to significantly decrease 60-day mortality compared to appropriate monotherapy 5.